The research will examine drinkers and drinking at outlets to identify social mechanisms by which drunken driving and alcohol-related violence are maintained in communities. Patrons in 165 bars in six California communities will be surveyed on exit from bars on weekend nights, followed by a phone survey. The exit survey will characterize drinking and social interactions that evening. The telephone survey will provide background measures of drinkers' characteristics and risk related behaviors (N H 1,620). Patron and staff interviews in select outlets identified by risk for drinking-driving and violence, together with bar observations conducted in a random sample of the total bars, will characterize social relations and norms that may reinforce problem behaviors. These qualitative assessments of bar social dynamics will inform and extend quantitative studies. Three hypotheses will be tested: (1) Greater neighborhood social disorganization will be related to greater rates of drunken driving and aggression among bar patrons. (2) Greater bar concentrations will be related to greater clustering of patrons across establishments correlated with risk characteristics. (3) Greater clustering by patrons will result in greater social cohesion in high-risk outlets. The short-term goal of the proposed research is to determine whether at-risk drinkers cluster across on-premise alcohol outlets and whether clustering is increased in areas with high outlet concentrations. The mid-term goal of the study is to initiate studies of social processes that maintain problem behaviors within outlets, identifying social structures that make problems resilient to change. The long-term goal is to provide communities with guidance on regulatory processes that may ameliorate neighborhood problems related to alcohol outlets.